Control System for Flexible Joint Robots

Control System for Flexible Joint Robots

This technology is a robust control system that resolves robot singularity issues by converting Cartesian coordinates into rotational coordinates and estimates internal and external disturbances using a disturbance observer based on the dynamic model of flexible joints, reflecting them in the control input.

Conventional linear system-based disturbance observers suffer from performance fluctuations depending on robot movement, necessitating conservative design, and their operational range is limited due to control divergence when singularities occur within the workspace.

This technology utilizes a Jacobian transpose matrix to transform coordinate systems and designs a nonlinear disturbance observer that includes a determinant to eliminate inter-joint reaction forces, thereby achieving consistent control performance and singularity avoidance regardless of changes in robot posture. It can be applied to rehabilitation training, gait assistance, and medical/welfare services, maximizing the workspace and improving robot performance and efficiency by achieving high performance and stability across various fields.

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Key Features:

• A full flexible joint robot dynamics unit that receives control inputs and disturbances, and outputs a control output by multiplying the control input, which reflects the disturbances, by at least one determinant.
• A control input dimension conversion unit that receives the robot's control input and converts the Cartesian coordinate system of the control input into a rotational coordinate system.
• c2 is the distance between the end of the second link and its center of gravity, and is the angle of the second link in the Cartesian coordinate system.
• A disturbance observer that calculates estimated disturbances by estimating disturbances and reflects the estimated disturbances in the control input.

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This invention was developed with the support of the Ministry of Trade, Industry and Energy's technology development project for interoperable modular muscle-assist exosuits.